Heat-actuated gas-pump.



U. A. ANDERSON. HEAT AGTUATED GAS PUMP.

APPLICATION FILED 33.25, 1909.

Patented Mar. 28, 1911.

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UNITED STATES PATENT OFFICE.

CHARLES A. ANDERSON, OF CHICAGO, ILLINOIS.

HEAT-ACTUATED GAS-PUMP.

T 0 all whom it may concern:

Be it known that 1, CHARLES A. ANDER- SON, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Heat-Actuated Gas- Pumps, of which the following is a specification.

The invention relates to improvements in heat-actuated gas pumps and has among the salient objects to provide a pump which is operated automatically by the very gas which it serves to circulate; to provide as a part of a closed circulating system a pump which is so organized that heat continuously supplied to two preferably similar cylinders or chambers effects the reciprocation of oppositely moving gas displacers within said cylinders, which movement operates to draw in and compress successive charges in the two chambers alternately; to provide an apparatus of the character described in which the compression of the circulating gas is effected by heating it, as distinguished from the usual method of compressing mechanically; to provide an apparatus which dispenses with the use of cylinder fitting pistons and thus eliminates the many difiiculties incident to their use in high pressure systems; to provide an apparatus which is peculiarly suitable for circulating carbon dioxid or other high pressure gas; to pro vide an apparatus which reduces to a minimum the use of valve mechanism so that the apparatus may operate almost indefinitely without any attention whatever; to provide an apparatus which when utilized for refrigerating purposes is of high efficiency; to provide an apparatus which is especially suitable for embodiment in small sizes, so that it may be used for small refrigerating plants, such as for domestic purposes, for butcher shops, saloons, etc., and in general to provide an improved apparatus of the character referred to.

The invention consists in the matters hereinafter described and more particularly pointed out in the appended claims.

In the drawings Figure 1 is a vertical sectional view of my improved device, and Fig. 2 is a similar sectional view taken at right angles to the view shown in Fig. 1.

Describing now more particularly the mechanical construction of my pump, 1 designates as a whole the base casting which is provided centrally with a cylindrical jour- Specification of Letters Patent.

Apphcation filed February 25, 1909.

Patented Mar. 28, 1911. Serial No. 480,035.

nal box or walking beam chamber 2 in which is mounted the walking beam and connected parts hereinafter more particularly described. The upper end of this casting is vertically bored at either side as shown at 3, 3, the lower end of these bores communicating with the walking beam chamber 2 as shown in Fig. 1. Within the upper end of each of these cylindrical bores 3 is screw threaded a hollow supporting stud 4, and upon these studs is mounted a cylindrical block or casting 5 which is rigidly united to the studs 4: by means of a sleeve 6, and serves as an end closure member for the gas cylinders hereinafter described. In order to secure a tight connection between the sup porting block and the studs 4 a packing 7 is preferably inserted between the lower base of the block 5 and the shoulder 8 of the sleeve 6. Upon the upper end of this easting 5 is mounted a pair of elongated. cylindric gas chambers 9 and 10 respectively, parallel with each other and slightly spaced apart. These gas chambers may be secured to the end closure member 5 by suitable screw-threaded connections as shown at 11.

If desired a packing 12 may be inserted between the upper edge of the casting 5 and the ends of the gas chambers. Within each of these gas chambers is mounted to reciprocate an elongated hollow displacer 13, 14 respectively. These displacers are suitably yoked together to operate in timed relation, sot-hat one dis-placer will be ascending while the opposite one is descending. To this end each displacer is provided with a stem 15 which reciprocates through a metal tubing 16 seated in the end casting 5 and extending into the corresponding tubular stud 1. The lower end of each of these displacer stems extends into the walking beam chamber 2 in the base casting, and is there pivotally connected to one end of a walking beam or rocking lever 17 by means of a link 18. This walking beam 17 is keyed or otherwise secured to a rock shaft 19 journaled in the sides of the base casting 1. One end of this rock shaft 19 extends through the side of the base frame and is provided with an up standing arm 20 rigidly secured to the rock shaft in' any suitable manner.

Upon the outer side of the base frame 1 is mounted a pair of ear like brackets 21, within which is rotatably journaled a shaft 22 one end of which carries the fly-wheel 23. The other end of this shaft is operatively connected to the arm 20 of the walking beam by means of a link 24, one end of which is pivotally connected as shown at 25 to an arm 25 carried by the shaft 22 and the other end of which is similarly connected to the arm 20 as shown. at 26. From the foregoing it will be seen that the displacers are yoked together to operate in timed relation and are likewise operatively connected to the fly wheel.

Each of the valve stems 15 is made to serve as a valve mechanism, and to this end is axially bored throughout that portion of their length next to the displacer as shown at 26, 27 respectively. The axial bore 26 is intersected by three ports designated 28,

29 and 30 respectively. The axial bore 27 of the opposite stem 15 is provided with similar intersecting ports designated 31, 32 and 33 respectively. These ports just described are so disposed that when the displacers are at their limits of movement in either direct-ion the two gas chambers are placed in communication with each other through the axial bores of the stems 15 and through a cross passage or duct 34 which is formed to extend transversely through the end wall casting 5. For example, when the displacers are in. the position shown in Fig. 1, the intermediate port 29 of the displacer 13 will register with one end of the duct 34, while the lowermost port 33 of the other displacer registers with the opposite end thereof. hen the position of the dis placer is reversed, the lowermost port 30 of the displacer 13 and the intermediate port 32 of the opposite displacer 14 will register with the corresponding ends of the duct 34.

In the present instance the pump forms part of a closed circulatory system such as may be used for small refrigerating plants, and accordingly each gas chamber is connected to the gas inlet pipe 35 and a small outlet pipe 36. Within the inlet pipe 35 is interposed a check valve 37 so arranged as to prevent any gas escaping from the gas chamber into the inlet pipe, while the outlet pipe 36 is provided with a similar check valve 37 arranged however in exactly the reverse manner. The upper end of each of the gas chambers is provided with a suitable gas burner 38, in order to heat the gas in the upper ends of the respective chambers. These burners, however, form 110 part of the present invention and need not therefore be more particularly described. Preferably each gas chamber is also provided with a water jacket 39 in order to more speedily cool the gas in the lower part of the respective cylinders.

Describing now' the theory and operation of my invention, the upper ends of the gas cylinders are continuously heated by the burners 38 while the lower ends of the chambers are kept cool by means of water or other cooling medium circulated through the water jackets 39. The gas used to accomplish the refrigerating may be carbon dioxid although other circulating mediums may be used. Assuming that the apparatus is in the position shown in Fig. 1, it will be noted that the two chambers 9 and 10 are in communication with each other through the by-pass 3 1, and accordingly the pressure will be equalized and be the same or substantially the same in both of the chambers. In practice the carbon dioxid is delivered from the pump to the circulating system through outlet pipes 36 at approximately eight hundred pounds pressure and returned to the intake side of the pump through the pipes at approximately four hundred pounds pressure. These figures may, of course, be varied but I have found that in small refrigerating plants about the above pressure is required. It may behere stated that the pressure of the as it travels through the system is lowered by means of a reducing valve, not shown, or in any other well known manner.

Inasmuch as the pressure in the two chambers is equalized when the high pressure side is vented into the low pressure side the equalization of the pressure in the two will produce a pressure of approximately six hundred pounds. While the rocking lever or walking beam operates in a sealed chamber and the fit of the displacer stems in the passages which lead from the gas chambers to the walking beam chamber is such that there is practically no leakage of gas from one to the other; nevertheless it is practically impossible to make an absolutely closed working joint and accordingly the pressure in the walking beam chamber will usually be in the vicinity of the mean be-. tween the maximum and minimum pressures which obtain in the two gas chambers. Inasmuch as this mean pressure is approximately six hundred pounds it may be assumed that the same pressure exists in the walking beam chamber. At the instant prior to the cross venting from one chamber to the other, the outlet check valve 37 of the then high pressure cylinder will be open and gas delivered to the high pressure side, while at the same instant the inlet check valve 37 of the low pressure cylinder will be open and the latter taking in gas at approximately four hundred pounds pressure. By this means the gas will be thermally circulated through the system as long as the pressure in the two chambers is alternately raised and lowered above and below the mean pressure in the system proper.

The manner of eifecting the changes in pressure so as to force the gas under maximum pressure into the system from one chamber of the pump and at the same take the gas at minimum pressure into the other chamber will now be described. When the displacers are in the position shown in Fig. 1, the two chambers are in communication and the pressure will accordingly be equalized. In other words the pressure in each cylinder will be at approximately six hundred pounds and accordingly the respective check valves 37, 37 will be closed. In other words the back pressure of the gas against the inlet check valves 37 will be greater than the four hundred pounds pressure on the op posite side thereof; while the pressure against the outlet valves 37' will not be sufficient to open these valves and force the gas into the system. The displacers however will remain only momentarily in the position shown in Fig. 1 because the momentum of the fiy-wheel will carry the walking beam past the dead center, reversing the latter and starting the upper displacer down and the lower displacer up. This at once closes communlcation between the two chambers, 13, 14: inasmuch as the ports 29 and 33 instantly pass out of register with the cross vent 34. As the displacer 1 1 descends, the gas in its chamber will be gradually transferred from the lower to the upper end of the cylinder, passing in the form of a thin sheet or film to that part of the cylinder which is heated by the burner 38. Accord ingly as fast as the gas arrives in the upper end of the cylinder 10 it will reach a comparatively high temperature. This gas as it expands will, through its own pressure, continue to drive the displacer 14 downwardly, until the displacers are in a position reverse of that shown in Fig. 1.

Precisely the reverse conditions take place in the opposite cylinder 9. Displacer 13, as it rises, forces the heated gas downwardly so that the latter passes in a thin sheet past that portion of the wall of the cylinder which is subject to the cooling action of the water jacket. The gas when it reaches the lower end of the cylinder is at a relatively low temperature and below the four hundred pounds pressure on the return side of the circulating system. Before the descending displacer 14 has reached the limit of its downward stroke the pressure of the gas in the cylinder 10 will have reached approximately eight hundred pounds. Inasmuch as this pressure is greater than the pressure in the pipe 36, the check valve 37 will be opened and a certain amount of gas will flow into the receiving or high pressure side of the system. At the same time the pressure in the opposite cylinder 9 will have fallen below four hundred pounds whereupon the check valve 37 of this cylinder will be opened and a certain amount of gas taken into the cylinder 9.

From the foregoing it will be seen that at the instant of porting between the two cylinders the pressure in each cylinder in the walking beam chamber is substantially equal. The momentum of the fiy-wheel will, however, carry the displacer far enough to close the ports and start the displacers to moving in the opposite direction. Thereupon the pressure will continue to rise in the cylinder in which the displacer is descending, and inasmuch as the pressure in that cylinder starts at approximately six hundred pounds it will be seen that as soon as it rises abovethat through the action of the heat, the increase in pressure will tend to force the displacer downwardly. At the same time the pressure in the opposite cylinder, starting also at six hundred pounds, or thereabout, will decrease during the ascent of its displacer as the gas is cooled and transferred into the lower end of the chamber. The lowering of pressure in the lower end of the cylinder is due to the relatively cold walls thereof; it being noted that the gas passes over these walls in a thin sheet in reaching said lower end. The displacer-s perform their functions as such, and also with their stems constitute differential pistons; the effective piston area of each being the cross-sectional area of its stem. It will be remembered that the pressure in the walking beam chamber is practically constant, in other words, it remains approximately six hundred pounds. Accordingly this pressure is effective in acting upon the stem of that displacer which is rising inasmuch as the pressure of the gas in the cylinder of this displacer is being gradually lowered. Inasmuch as the only resistance to movement of the mechanism is the slight mechanical friction of the working parts, and the slight gas friction incident to the displacing of the gas, it is obvious that no great amount of mechanical energy is.required to operate the device, and it has been found in practice that the pump will work at ample speed to be eflective in" com ressing the gas into liquid form and e ectively circulating it for the purposes described.

While I have herein shown a practical embodiment of my invention it is of course apparent that it may be more or less varied in details of construction without in any manner departing from the spirit of the invention.

I claim as my invention:

1. I11 a gas pump, the combination with a substantially sealed chamber having gas therein at an approximately uniform pressure, of a pair of gas cylinders, a reciprocatory displacer in each of said cylinders, an actuating rod connected to each of said displacers and extending into said sealed chamber, means for connecting said actuating rods to operate in timed relation, means for alternately supplying gas to and venting it from said cylinders, and means for varying the pressure in said cylinders alternately above and below a substantially uniform pressure in said sealed chamber.

2. In a gas pump, the combination with a sealed chamber having gas therein at asubstantially uniform pressure, of a pair of gas cylinders, a reciprocatory displacer in each of said cylinders, an actuating rod connected to each of said displacers and extending into said sealed chamber, means for alternately raising and lowering the pressure in said cylinders above and below the substantially uniform pressure in said sealed chamber, and means for supplying gas to and venting it from the respective cylinders.

3. In a gas pump, the combination with a walking beam chamber having gas therein at a substantially uniform pressure, of a pair of cylinders, a reciprocatory displacer in each of said cylinders, an actuating rod connected to each of said displacers and extending into said walking beam chamber, a walking beam mounted in said chamber, and connected to the respective actuating rods, means for automatically effecting the reversal of said walking beam at the end of the respective strokes of the displacers, means for supplying gas to and venting it from said cylinders, and a burner for continuously supplying heat to one end of said cylinder.

4. In a gas chamber, the combination with a sealed chamber having gas therein at a substantially uniform pressure, of a pair of gas cylinders, a displacer in each of said cylinders, an actuating rod connected to each of said displacers, means for eifecting the reversal of said actuating rods at the end of the respective strokes of the displacers, means for supplying gas to and venting it from said cylinders, and means for supplying heatto one end of each of said cylinders.

5. In a gas pump, the combination with a sealed chamber having gas therein, of a substantially uniform pressure, of a pair of gas cylinders, a reciprocatory displacer in each of said cylinders, actuating mechanism connecting said displacers, means for alternately raising and lowering the pressure in said cylinders above and below the substantially uniform pressure in said sealedchamber, and means for supplying gas to and venting it from the respective cylinders.

CHAS. A. ANDERSON. Witnesses:

ALBERT H. GRAvEs, EMILIE Rosa.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Iatents, Washington, D. G. 

